92 Biographical Account of [Feb. 



him the Copleyan medal. His different volumes on air were 

 published in succession, while lie lived with Lord Shelburnej, 

 and while he was settled in Biroiingham. They drew the atten- 

 tion of all liurope, and raised tiie reputation of this country to 

 a very great height. 



The first of his great discoveries was ?dtrous gas, which had 

 indeed been formed by Dr. Hales ; but that philosopher had not 

 attempted to investigate its properties. Dr. Priestley ascertained 

 its properties with great sagacity, and almost immediately 

 applied it to the analysis of air. it contributed prodigiously to 

 all subsequent investigations in pneumatic chemistry, and in 

 some measure lead to our present knowledge of the constitution 

 of the atmosphere. The next grand discovery was oxygen gas, 

 to which we are indebted for the revolution which chemistry 

 soon after underwent. This substance, however, would have 

 been discovered independent of Dr. Priestley; for Scheele 

 announced it, and founded on it an analysis of air ; and there is 

 every reason to believe that he was ignorant of what Dr. Priestley 

 had done, though his book was not published till three years* 

 after Dr. Priestley had actually announced his discovery to the 

 public. Lavoisier, likewise, laid claim to the discovery of 

 oxygen gas ; but his claim is entitled to no attention, and is 

 inconsistent with that candour which he displayed on other 

 occasions ; for Dr. Priestley prepared oxygen gas in Mr, 

 Lavoisier's house in Paris, and showed him the method of pro- 

 curing it during the year 177"^? ^ considerable time before 

 Lavoisier's pretended discovery was made. 



To Dr. Priestley we are likewise indebted for the discovery of 

 most of the other gaseous bodies at present known, and for the 

 investigation of their properties. Indeed, carbonic acid, hydro- 

 gen, sulphureted and phosphureted hydrogen, and oxymuriatic 

 'dcid, are almost the only ones for which we are not indebted to 

 him. Sulphurous acid, fluoric acid, muriatic acid, ammoniacal^ 

 carbureted hydrogen, carbonic oxide, and nitrous oxide gases, 

 were all first produced and investigated by him. Though he did 

 not discover hydrogen gas, yet his experiments on it were highly 

 important, and contributed essentially to the revolution brought 

 about in chemistry. Nothing, for example, could be more 

 striking than the reduction of oxide of iron, and the disappear- 

 ing of hydrogen when the oxide (or finery cinder, for it was that 

 which he used) is heated sufficiently in contact with hydrogen 

 gas. Azotic gas wa$ discovered before he began his career ; but 

 we are indebted to him for most of the properties of it yet 

 known. To him also we owe the first knowledge of the acid 

 produced when the electric spark is taken for some time in 

 common air ; a fact which led afterwards to the knowledge of 

 the constituents of nitric acid^ which contributed so essentially 



